Process for grouting cracks and contraction joints



iatented Sept. 8, 1936 UNlTED STATES PATENT OFFICE,

PROCESS FOR GROUTING CRACKS AND CONTRACTION JOINTS Lars R. Jorgensen, Berkeley, Calif.

No Drawing. Application April 27, 1935, Serial No. 18,624

9 Claims. (Cl. 72106) For grouting contraction joints or cracks in a m ssly e te ed t a large extent y the ddams or other material, buildings, arches or dition to the mixing water of various substances, cracks and pores in sandstone or other rock, it such as sugar, molasses etc., or other setting may be expedient to use a system of grout pipes retarder, in predetermined quantities. The acas is in common use, but instead of employing tion of setting and ultimate hardening is ap- 5 plain cement grout I propose to use a grout conproximately as follows: The plaster of Paris sisting principally of a mixture of Portland cecrystallizes faster than the Portland cement hyment and plaster of Paris, or Portland cement, drates and has the tendency to rob the Portland plaster of Paris and pumicite or celite or a like cement of the water necessary for its complete hyproduct. dration so that a mixture more plastic than 10 The plaster of Paris grout alone expands in elastic results. volume about three-tenths per cent, when Some time after the water in the reservoir has setting. Portland cement grout alone contracts wetted the upstream face of the dam, water will when setting, but by mixing the two together a be available by means of capillary action for the combination can be obtained, which is about Portland cement to take up the amount it lacked neutral in this respect and this is one feature for complete hydration and the grout will then which is taken advantage of in this invention. become harder and more elastic. This happens The relative proportion of the mix may vary mainly after the grout has undergone the squeeze from mostly Portland cement to mostly or all that made it flow from areas of high compression plaster of Paris. towards areas of low compression or tension. 20

The combination is much more plastic than In some cases a decomposition of the grout Portland cement alone and the modulus of material may take place some time after the dam elasticity, if any, of the combination is much has been in use, due to the sulphate composilower than that of Portland cement grout. tion of the plaster of Paris in the presence of These two features are important in ordinary moisture. This will be accompanied by a slight 25 building construction, but are especially imporexpansion, which is advantageous. The contractant in arch dam construction for filling the tion joint ought to be provided with grout stops artificial cracks left between the individual blocks along both the upstream and downstream face or voissoirs after the concrete or masonry has and with recesses on the faces of the contraction set and contracted. joints, so as to keep all the grout material in the 30 These joints, artificial or otherwise, generally joint. p p a maximum during the month of March, In order that the Portland cement may take in the Northern Hemisphere and this is therefore a considerable part in the initial hardening procthe p p time to fill these openings with rout. ess of the grout, it is sometimes desirable to mix When an arch or arch dam is loaded the stresses th Portland cement grout first and some time 35 are not uniformly distributed across the section. later mix th plaster of Paris grout and then This stress distribution will however be made quickiy mix t t grouts in t correct propormore uniform after the injection of my improved tion just before this mixture is conveyed by the grout mixture in the contraction joints and this grout pump, g av ty 0 y other Suitable means is also a feature of my invention. t it final place of deposit. 40 Th s g t mixture is Very Plastic after Setting In order to better prepare the sides of conand therefo e s" considerably When the lead traction joints or the cracks in dams, buildings, comes on. a pl f greater unit Compression arches and other construction, or cracks in rock and flows to places of less compression, thereand other material, for the reception of grout,

by tending to equalize the Stresses across the it is often desirable to inject into the joints, cracks section at eve y J which in turn influences or voids a mixture consisting of diluted sodium d an y the stress distribution in the silicate and diluted calcium chloride, or diluted whole b ock bet e t .l' sodium silicate in combination with any diluted As a general u a smaller u t f mixing chemical capable of forming agelwith the sodium 5 water makesabetter grout than otherwise. Consilicate. If desirable, most of the gel can be slderation has however to be given to the time emptied out again by means of compressed air it takes for the mixed grout to reach its ultimate or the like.

place of deposit, as this time must be shorter This process will leave a wet slippery skin on than the setting time. The setting time can be the side walls, where the separation of these walls 55 is considerable, and it will fill the cracks where these are so fine that no grout can penetrate.

The grout is then injected in some usual manner. This grout may consist of ordinary Portland cement grout or a mixture of Portland cement and plaster of Paris as described above. The mixing fiuid for this grout may be either plain water or a diluted gel formed by mixing diluted sodium silicate with a diluted chemical capable of forming a diluted gel with the sodium silicate. This diluted gel mixing water will allow a drier grout to be used since it makes the grout easier flowing and more capable of penetrating fine cracks. Such grout also has but small volume change.

Where cracks are difficult to close watertight, some surplus of sodium silicate may be left in the gel mixing water. After the grout has been injected, carbon dioxide gas under pressure is admitted. This gas will then combine with the surplus sodium silicate and close up permanently any small cracks left. Any gas which will react with the sodium silicate to set silica free may be used.

For cracks and voids in sandstone, or other rock, in places where there are no waterstops provided, a plain cement grout may be used to advantage in combination with a gel in the mixing water, since the presence of the gel makes it possible to get more grout into the openings to be closed up, than it would be without the gel. The resulting shrinkage is also less mainly due to the drier workable mix that can be used.

In general the chemicals or the fluid grout is pumped or otherwise forced into conduits built into the new structure, or the conduits may be introduced into existing structures.

Celite is a diatomaceous earth product.

While I have referred to various details, yet these may be changed without departing from the spirit of my invention, the scope of which is defined in the appended claims.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:-

1. A process of filling and solidifying the open space in contraction joints or other voids which comprises injecting into said void a gel in solution and then injecting sufficient grout mixture so that the void will be filled, said grout mixture possessing great plasticity when first set and developing practically no change in volume while setting, said grout mixture containing a setting retarder.

2. A process of filling and solidifying the open. space in a contraction joint in structures or a crack in rock or the like which comprises injecting into the joint or crack a gel in solution and then injecting a fluid grout of a calcium sulphate-like cement, Portland cement and water, the time of setting of said grout being delayed by preparing the Portland cement part of the grout some time in advance of mixing the calcium sulphate-like cement grout therewith, the grout being in such an amount that the void will be filled.

3. A process of filling and solidifying the open space in contraction joints in structures, voids in rock, or the like which comprises injecting into the joint, crack, or void a gel in solution and then a sufiicient quantity of a plaster of Paris and Portland cement grout containing a setting retarder so that the empty space will be filled.

4. A process of filling and solidifying the open spaces in contraction joints, or other open voids or cracks which comprises injecting a gel in solution, removing most of it, and then injecting such a quantity of a plaster of Paris and Portland cement grout containing a setting retarder that the space will be filled.

5. A process of filling and solidifying the open spaces in contraction joints, cracks in rocks and voids in loose material, or the like, which comprises injecting into the voids or cracks a gel, thereafter injecting a grout having a gel in the mixing water, the amount of said grout being so great that the entire open space is filled.

6. A process of filling and solidifying the open spaces in contraction joints or other open joints or cavities which comprises wetting the sides of the joints or cavities with a sodium silicate solution and then injecting a plaster of Paris-Portland cement grout, water of which contains calcium chloride dissolved therein and a setting retarder, the amount of said grout being so great that the entire open space is filled.

7. A process of filling and solidifying the open spaces in contraction joints or other open joints or spaces by wetting the sides of the joints or spaces with a diluted sodium silicate solution followed by the injection of a plaster of Paris and Portland cement grout, the water of said grout containing chemicals capable of combining with the grout and with the sodium silicate, the mixing water also containing a setting retarder, said grout filling the entire open space.

8. A process of filling and solidifying the open spaces in contraction joints or other voids by wet ting the sides of the joints with a sodium silicate solution, followed by the injection of a plaster of Paris-Portland cement grout having a setting retarder in the mixing water, and this again followed by the injection of a carbon dioxide gas, the amount of grout being such that the entire open spaces are filled.

9. A process of filling and solidifying the open spaces in contraction joints or other voids by wetting the sides of the joints with a sodium silicate solution, followed by the injection of a plaster of Paris-Portland cement grout, and this again followed by the injection of a gas capable of forming a gel with the sodium silicate, the amount of grout being such that the entire open spaces are filled.

LARS R. JORGENSEN. 

